An Experiment in Randomness

You can print a random number between 1-10 with the following command.

echo $((( RANDOM % 10 )+1))

Creating random numbers

If you change it so the output is between 0-9 you get decently even results.

cat /dev/null > random.txt && cat /dev/null > random2.txt && for ((i=0; i<=9999;i++)); do echo $((( RANDOM % 10 ))) >> random.txt ; done && for ((i=0; i<=9;i++)); do echo $(grep -c $i random.txt) $i; done  |  sort -n

Note that you can change the command to be between 1-10, but all the 1’s in 10 will get grepped and counted as 1’s.

The above command should return something similar to the following. Sorted by lowest occurrences first.

943 5
945 8
985 7
996 2
997 6
1005 3
1012 9
1016 4
1033 0
1068 1
admin@localhost:~$

We can plot them in LibreOffice Calc.

Plot with GnuPlot

Gnuplot is another utility that you can use to plot numbers. Example is below.

cat /dev/null > random.txt && cat /dev/null > random2.txt && for ((i=0; i<=9999;i++)); do echo $((( RANDOM % 10 ))) >> random.txt ; done && for ((i=0; i<=9;i++)); do echo $i $(grep -c $i random.txt) ; done  |  sort -n | gnuplot -p -e 'plot "/dev/stdin"'

wget multiple links with random access times

Create a file “list.txt” that contains all the URLs you want to download and launch the following command

for i in cat list.txt ; do wget ${i} && sleep $(( ( RANDOM % 120 ) +1 )) ; done

It’ll now run and after each link will wait a random amount of time up to 120 seconds before downloading the next link. Change the number as needed.

Bash random sleep timer

Change the 10 to however many seconds you need or want.

echo $(( ( RANDOM % 10 ) +1 ))

Example output

bob@localhost:~$ echo $(( ( RANDOM % 10 ) +1 ))
10
bob@localhost:~$ echo $(( ( RANDOM % 10 ) +1 ))
2
bob@localhost:~$ echo $(( ( RANDOM % 10 ) +1 ))
9
bob@localhost:~$ 

Sleep timer

sleep $(( ( RANDOM % 10 ) +1 ))